how interchangeable are ecu's?

[l1ttle_d3vil]

http://www.club4ag.com/faq%20and%20tech ... 04A-GE.htm

i currently have an 1984-1985 ae86 ECU (as shown on the website above) plugged in to my car, but have some weird problems and its something to do with my wiring or signals or something.
i have just bought a 1986-1987 ae86 ECU.

i am using an ae86 loom on a fwd engine converted to rwd so don't know what it was out of originally. i am also using a distributor that didn't go with the ae86 loom, so don't know what thats off either.

now will it do anything any harm if i plug the later model ECU in to see if it makes any difference? (after making sure the right wires go to the right pins ofcourse). or am i likely to blow something up by using a different ecu?

my original ecu looks a bit beaten up and has been dropped a few times and im having weird problems with my car. it will run, then not run, fire then not fire and all that sorta sh*t. ive got a feeling its something to do with the signals the injectors are getting from the ecu, which could go all the way back to the distributor too.

cheers

[suberimakuri]

well, the later ecu that you have does run a slightly different loom.
But you can run it.

[l1ttle_d3vil]

ok so aslong as i get the wires going to the right pins on the ECu it shouldn't do any harm.

will a distributor run ok with any bluetop ECU? or will different model ecus (like mentioned above) tell the distributor different things?

[suberimakuri]

all bluetop distributors have same pinouts, colour varies, but it doesn't matter.

just plug it in and start it up.

[ChaosAD]

Or does he have a red/blactop dizzy?
Pull the dizzy cap off and there should be two wheels in it. one should have 4 teeth and the one below it should have quite a few more (about 24 teeth, I think).

[l1ttle_d3vil]

Or does he have a red/blactop dizzy?
Pull the dizzy cap off and there should be two wheels in it. one should have 4 teeth and the one below it should have quite a few more (about 24 teeth, I think).

yup that sounds about right - is the one you described a bluetop dizzy? are redtop ones different?

[l1ttle_d3vil]

well i went down tow ork and tried to start it up this morning, wouldn't run any good. swapped ecu's, and it ran fine, started easy, idled no problem. so i took the new ecu out and put the old one back in and had the same problems, new one back in and it went fine.

so hopefully thats all the problem was (that my ecu was stuffed). but then again im wondering why it ran like it did last week if the ecu was stuffed, then stopped after a while. i guess only time will tell